The present invention relates to isolator valves. More particularly, the present invention is directed to isolator valves for preventing flow to or from directional valves and the like to protect personnel from injury as well as preventing unwanted spillage and to perform tests on the hydraulic circuit incorporating the isolator valves without disassembly.
Hydraulic directional valves direct pump flow into actuators which may be cylinders, motors or the like. Directional valves, such as a directional valve Dv shown in the system 10 of FIG. 1, are designed as stackable modules typically mounted upon sub-plates such as the sub-plate SP shown in FIG. 1. The sub-plate SP, has ports PT at appropriate places about the housing of the sub-plate for respectively coupling a tank 14 and a pump 16 to one set of ports, the ports of the directional valve Dv and the ports 12a and 12b of an actuator 12. The necessary ports may be on the sides or the bottom of the subplate. If the subplate is longer than the modules stacked thereon, see FIG. 13, the ports may be on the top of the subplate in a region displaced from the modules.
The directional valve Dv shown in FIG. 1 is operable to block flow, direct flow from pump 16 into port 12a and flow to tank 14 from port 12b or alternatively to direct flow from pump 16 to port 12b and direct flow from port 12a to tank 14. The pump 16, tank 14 and actuator 12 are coupled to the sub-plate ports by suitable piping P. The sub-plate serves to couple hydraulic devices between the input (pump) and output (tank) devices and the load device (actuator). Although no modules are shown stacked on the subplate of FIG. 1, it should be understood that a number of such modular devices may be stacked upon the sub-plate.
The sizes of the directional valves and sub-plates as well as the number and location of ports and flow paths are typically in accordance with national and international standards. The United States uses the NFPA standard whereas the DIN and ISO standards find commonplace use in Europe. Depending on the particular application, the directional valve Dv may be mounted upon the top of other modular or “sandwich” valves which provide functions other than directional functions, i.e. pressure relief, counter-balance and the like. Note, for example, FIG. 13 which shows three (3) stacked hydraulic circuits, C1 through C3, each stack having directional valves Dv mounted upon modular or sandwich valves Sv, Sv′ and Sv″, which in turn are mounted upon common sub-plate SP. The sub-plate is provided with ports SPT for connection to appropriate tubing or other conduits in order to interconnect other components of the hydraulic system such as, for example, a pump and a tank (not shown).
FIGS. 14 and 14a show further details of a typical modular or “sandwich” valve arrangement. FIG. 14 shows a sectional view of a hydraulic circuit comprised of stacked modular components which includes a base or sub-plate SP and modular valves Sv, Sv′, Sv″ and Sv′″ which are stacked in that order upon the sub-plate SP. A directional valve Dv is mounted upon modular valve Sv′″.
FIG. 14a shows a simplified hydraulic circuit in schematic form and representing the modular components shown in FIG. 14. In the example given, the sub-plate SP has ports P and T respectively for coupling a pump and tank thereto, typically by suitable piping. The output ports A and B are coupled to a load device, also by suitable piping. The relief modular valve Sv and the check modular valve Sv′ are coupled between the ports P and T and directional valve Dv. The check modular valve Sv′″ and the flow regulator modular valve Sv″ are coupled between the directional valve Dv and the output ports A and B. The modularity allows any type of hydraulic circuit to be set up without the need for piping simply by stacking. However, these systems lack the ability to enable the performance of certain tests and lack the capability of preventing spillage and/or harm to operating personnel at times when the hydraulic circuit must be disassembled for inspection, maintenance, repair or replacement.